focus problem on a zenith
 

Ive got a 26KC20 zenith color chassis with a big focus problem. The 1V2 is arcing inside the tube, looks like this was a previous problem as when I got the set, the 1V2 was missing and the socket is a little burnt up from this. The socket was smoking with a new 1V2. It appears that this was repaired in the past, I can tell by the bad soilder joints on a "new" 1v2 socket, which obviously didnt help. I did some resistance checks nearby and it all seems ok, since the filament of the 1v2 is in series with a winding off the flyback, is it possible the flyback has developed some kind of short? Like I say, the 1v2 is arcing from inside, down the the pins of the tube. Very wierd. Ive never seen this happen before

Here's what to do:

Unplug the CRT Socket and turn on the set.
If the problem goes away, you have a bad CRT.

If the problem stays, you may have a bad filiment lead on the focus tube or a carbon trail in the socket. (Make sure that the socket that was put in is "New". Make sure it's wired right

When I worked for RCA we had a solid state replacement for the 1V2 and 2AV2. It is a simple job to install and if you like the look of the 1v2, you can leave it in place. I just put one in one of my CTC 4's. I also use a solid state replacement for the HV rectifiers as well. These perform much better than the HV tubes, create less X-Ray, less heat, and no-one cares becase they are inside the cage and you cant see them. :D You can then remove the filiment wire from the tubes, eliminating a potential problem.
I have both parts. The HV solid state is a plug in, The focus rectifier is a solder in diode. You can E-Mail if you like.

Thanks,
Kirk

HI Kirk,

The problem here was a carbon build up in the socket. Ive had this happen many times with zenith damper tubes, the carbon actually glows like a light bulb and smokes pretty good too! The carbon acts like a resistor and causes all kinds of odd problems. I replaced the socket and everything is back to good order.
Thanks for your help, Doug